Foley catheters have 1-way, 2-way or 3-way variations. The 1-way catheter is a simple tube used to remove urine without securing the tube, and is used when someone is "straight catheterized." The 2-way tubing has an outlet for urine and a conduit for water inflation of the catheter's balloon. The three-way tubing has an outlet for urine, an inlet for water inflation of the balloon, and an inlet for normal saline used for irrigating the urinary system most commonly for gross hematuria.
Foley Catheters are available in various different sizes and its range goes from 12FR (French Size) to 48FR. Generally, small size of Foley Catheters are preferred and mostly available as they are more comfortable but lager sizes are also used by the patients whose urine is thicker or contains high amount of sediments. http://www.sarahealthcare.com/foley-balloon-catheter.html